Originally Posted by user92626
Why is it called 'stretch-shortening cycle'?
I'm not subscribing to the method that you keep your arms loose and limp and just turn the body but I'm interested to understand.
I really don't know why it is called that. I'm sure there's a good technical reason, but I don't know what it is.
It isn't about loose and limp arms as much as loose wrist. The idea is that if your wrist is loose when you've taken back the racquet and dropped the head down... when you swing forward, the looseness of the wrist combined with the inertia of the weight of the racquet head will cause the racquet head to lag behind the arm as it swings forward.
Eventually, the muscle/tendons/joint within the wrist will be ultra-stretched (think loaded) to the point where it will start to be naturally unloaded like a rubber band. This can bring a great deal of racquet head speed.
I'm not sure how else to describe it. When a baseball pitcher or cricket bowler throws a ball, you have to have the same kind of wrist action.